In recent years, with advance in data communication technique and equipment of network environment, data exchange between a plurality of electronic apparatuses has been performed in various forms. Therefore, various mechanisms relating to data exchange between a plurality of electronic apparatuses have been proposed in the prior art.
Recently, as in offices, wireless LANs (Local Area Networks) are also being constructed in homes, and they are used to connect household electrical appliances such as televisions, HDD (Hard Disk Drive)/DVD (Digital Versatile Disc) recorders, personal computers (PC), and printers by wireless communication without cables.
For example, some HDD/DVD recorders and printers include a slot to store a portable medium such as an SD card (Registered Trademark) or the like. Therefore, there are increasing demands for remote control of portable media which are stored in HDD/DVD recorders and printers by wireless communication from a personal computer or the like.
Generally, communication between a plurality of household electrical appliances adopts a half duplex system or a communication system based on the same, regardless of wired or wireless communication. On the other hand, many portable media include a full-duplex interface. When a portable medium (which includes a full-duplex interface) stored in a household electrical appliance is operated by remote control from another household electrical appliance (which performs half-duplex communication), it is necessary to match the half-duplex communication part of the former with the full-duplex communication part of the latter.
However, communication between a plurality of household electrical appliances, that is, processing of the half-duplex communication part of the former is preferably minor processing which does not require the user to be conscious of matching the former with the full-duplex communication part of the latter.
In addition, some portable media can additionally have new functions. Therefore, even if commands which are processed in the full-duplex communication part of the latter are increased with the addition of new functions, it is preferable that the system can be operated without changing the processing of the half-duplex communication part of the former.